Gun launched kinetic energy penetrator

ABSTRACT

A kinetic energy penetrator assembly includes a motor casing having an aftpening. A nozzle with a nozzle opening is seated in the aft opening of the casing and confines expanding gases produced by burning propellant in the casing to a configuration for applying a thrust to the casing. An aft pusher plate is connected to a plug which plugs the nozzle opening and which has an aft space for receiving expanding gases. A penetrator rod is connected to the forward end of the motor casing and includes a bore riding sabot having substantially the same diameter as the diameter of the pusher plate and an aft portion of the motor casing. The penetrator assembly is meant to be launched from a gun with expanding gases in the gun barrel pushing against the pusher plate and ejecting the penetrator at some velocity from the barrel bore. An initiator carried in the pusher plate and nozzle plug begins to burn when it is exposed to the expanding gases in the gun barrel and, after a selected period of time, ignites propellant in the motor casing which first boosts the velocity of the penetrator assembly and thereafter sustains its velocity. The sabot is designed to peel away from the rod after the penetrator leaves the barrel for producing an aerodynamically advantageous configuration for the penetrator assembly.

STATEMENT OF GOVERNMENT INTEREST

The invention described herein may be manufactured, used and licensed byor for the Government for Governmental purposes without the payment tome of any royalties thereon.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates in general to ordinance and in particularto a new and useful rocket powered kinetic energy projectile which isdesigned to be launched from a gun.

It is known to fire projectiles from a gun which, in and of themselves,are either explosive or meant solely for penetration. The projectileattains all of its velocity by expanding gases in the barrel.

Projectiles are also known which include a small rocket motor. Themotors are ignited while the projectile is in the barrel of a gun-likestructure. The rocket motors provide all of the thrust for acceleratingthe projectile to its maximum velocity. This type of projectile has hadonly limited success. It has been found not to have the accuracy or becapable of obtaining the speeds of conventional passive projectiles.

SUMMARY OF THE INVENTION

The present invention is drawn to a kinetic energy penetrator rod whichincludes a rocket motor and which can be launched by a gun. The rocketmotor is ignited only after the projectile leaves the gun barrel.

A conventional gun with rifling can be used. Only moderate spin isnecessary for the inventive projectile however so that a slip-ring isprovided between the projectile and the rifling to transfer only alimited amount of spin to the projectile. This modest spin rate is usedprimarily to average out any thrust misalignments or manufacturingtolerances on the outer surface of the projectile. The projectile isaerodynamically designed for low drag and for aerodynamic stability inflight.

Accordingly an object of the present invention is to provide a kineticenergy spike or penetrator assembly which is adapted to be launched froma gun, and which comprises a motor casing having an aft opening, anignitable propellant in the casing for generating expanding gases, anozzle connected to the casing and closing the aft opening thereof, thenozzle having a nozzle opening for directing expanding gases of thepropellant out of the cases to produce a forward thrust on the casing,and a push plate engaged over the aft end of the nozzle and casing forreceiving expanding gases from a charge in the gun and for transferringkinetic energy of those expanding gases to the casing. A penetrator rodis connected to the forward end of the casing and has a forward gunbarrel bore rider sabot thereon. The outer diameter of the pusher plateand of the sabot are about equal to the inner diameter of the gun barrelfor establishing a proper alignment between the barrel axis and thepenetrator assembly axis. A slip spin ring is provided on an outersurface of the pusher plate for transmitting only some of the spin fromrifling of the gun to the penetrator assembly so that the penetratorassembly spins only a moderate amount when it leaves the gun barrel. Aninitiator is connected through the pusher plate and holds a nozzle plugwhich is seated in the nozzle opening. The initiator has a delay chargewhich is ignited by the expanding gases of the gun and which, after acertain period of time, provide an igniting flame through the initiatorto the propellant in the casing for igniting the propellant.

A further object of the invention is to provide such a penetratorassembly or spike wherein the propellant has an aft booster part and aforward sustain part for initially accelerating the spike and thereaftersustaining a thrust on the spike for the remainder of its flight.

A still further object of the invention is to provide a spike orpenetrator assembly which is simple in design rugged in construction andeconomical to manufacture.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this disclosure. For a better understanding of the invention,its operating advantages and specific objects attained by its uses,reference is made to the accompanying drawings and descriptive matter inwhich a preferred embodiment of the invention is illustrated.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a side sectional view, partially in elevation, of a spike orpenetrator assembly according to the present invention; and

FIG. 2 is a composite side elevational view of the spike as itapproaches the end opening of a barrel bore, and as it appears at aselected point in time after it has left the barrel bore.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings in particular, the invention embodied in FIG.1 comprises a spike or penetrator assembly generally designated 20.

The spike 20 includes a forward nose faring 12 which is connected to theforward end of a penetrator rod 14. Around the forward end of thepenetrator rod a bore rider sabot 16 is engaged. Sabot 16 rides the boreof a barrel shown at 60 in FIG. 2. Sabot 16 is made of soft metal orsynthetic material which breaks up after it leaves the barrel bore. Thesabot includes a dished forward space which catches air to facilitatethis break-up effect.

Rod 14 is connected to a rocket motor casing 18 by a connecter 19 havinga threaded bore 21 therethrough. Threaded bore 21 has two threadedportions. The forward threaded portion threadably receives a threadedaft end 15 of rod 14. The rear threaded portion of connecter 19threadably receives a forward threaded portion of a connecter nut 22.The head of connecter nut 22 has a rounded configuration for engagingagainst the rounded forward end of casing 18. The connecter 19 has arounded aft end for engaging the rounded forward end of casing 18.

A plurality of internal propellant supporting fins 24 are provided incasing 18. The fins extend radially and in known fashion. The propellanton fins 24 include an aft booster portion 25 which generates moreexpanding gas for providing a boost to accelerate the projectile. Theremainder of the propellant on fins 24 act as a sustain propellant whichsustains the velocity of the spike throughout the remainder of itsflight.

The open end of casing 18 is provided with an aft case closure 26. Anozzle 28 is seated in the closure 26 and defines a nozzle opening. Thenozzle opening is lined by a known nozzle liner 30 which protects metalparts of the nozzle from heat damage. The casing 18 also has aninsulated lining 32 which protects it from heat generated by the burningpropellant.

A nozzle plug 36 made of metal or synthetic material is frictionallyengaged in the nozzle opening and acts to plug the nozzle opening.

A generally cylindrical initiator 38 extends through a central openingof nozzle plug 36 and is held by a nut 44. The initiator 38 has acentral bore 40 which is blocked by a delay charge 42 which can beignited at its aft end by gases and which burns at a known rate toproduce a delay effect. After a known delay the burning delay charge 42will ignite the booster portion 25 of the propellant on support fins 24.Immediately after the booster portion has been burned the sustainportion of the propellant begins burning. The initiator 38 thus acts asdelay ignition means for igniting the propellant charge only after thespike 20 has left its launching barrel 60.

The spike includes an aft pusher plate 34 having a dished aft opening 46which is designed to accept the pressure of expanding gases in a gunbarrel and transmit the force to the casing 18. For this purpose pusherplate 34 is engaged against the aft end of the nozzle 28 and/or thecasing 18.

Initiator 38 is threaded into bore 48 of pusher plate 34 so that theplug 36 is held fast to the pusher 34. Pusher 34 includes an outerannular groove which receives a slip spin-ring 50 which slides with somefrictional resistance around the pusher plate 34 as a result of itsengaging rifling 62 in the barrel bore 60 (FIG. 2).

In operation and as illustrated in FIG. 2, the spike 20 is launched froma recoilless or standard gun having a barrel 60 with a bore whichincludes rifling 62. Rifling 62 imparts only some of its spin to thespike 20 over slip spin-ring 50. The forward end of spike 20 is heldaligned with the flight axis 8 by the sabot 16 which rides in the boreof barrel 60.

Expanding gases in the barrel which can be generated by a charge in thebarrel or a charge connected to the spike (not shown) and function topush against pusher plate 34 and thus eject the spike 20 at somevelocity from the end of the barrel 60. These expanding gases alsoignite delay charge 48.

As shown at the left of FIG. 2 at some selected time after the spike 20has left barrel 60, wind resistance has broken up and peeled away thesabot 16 and the propellant in the motor casing has ignited. This helpsto eject the nozzle plug 64 with its connected pusher plate 42 from theremainder of the penetrator. The boost portion of the charge then burnsfor a brief period to accelerate the spike 20 to a selected velocity.The sustain charge then ignites and burns through the remainder of theflight to sustain this velocity until a target is reached or until thesustain charge is expended.

The moderate amount of spin which is transmitted to the penetrator 20while it is in the barrel 60 acts to average out any thrustmisalignments or manufacturing tolerances on the outer surface of thespike 20. The outer configuration of the spike has been selected foraerodynamic stability. The parts are also distributed to establish acenter of gravity 6 (FIG. 1) which adds to the aerodynamic stability.

In practice, a gun with an appropriate charge is utilized to acceleratethe spike 20 to a speed of about two thousand feet per second. The delaycharge is selected to burn for about 20 milli-seconds. The boosterportion 25 burns for about 200 milli-seconds or less and then thesustain portion is ignited to sustain flight of the spike to its target.

The motor casing 18 as shown in FIG. 1 has a conical forward portion anda cylindrical aft portion which has the same diameter as the cylindricalpusher plate 34. The rod 14 is cylindrical and has the same diameter asthe forward end of connecter 19. The rear end of connecter 19 can flareout slightly to start the taper of casing 18.

The aft opening of casing 18 is slightly inwardly tapered to morepositively retain the closure element 26 and the nozzle 28 connectedthereto.

While a specific embodiment of the invention has been shown anddescribed in detail to illustrate the application of the principles ofthe invention, it will be understood that the invention may be embodiedotherwise without departing from such principles.

What is claimed is:
 1. A kinetic energy penetrator assembly adapted tobe launched from a gun barrel bore, comprising:a motor casing defining aspace and having an aft opening and a forward end; an ignitablepropellant in said casing space ignitable to generate expanding gases; anozzle connected to said casing and closing said aft opening thereof,said nozzle having a nozzle opening for directing expanding gases out ofthe casing to produce a forward thrust for the casing; a pusher plateengaged with an aft end of the motor casing and adapted for transmittingthe thrust of expanding gases at an aft end of the pusher plate to themotor casing; a nozzle plug connected to the pusher plate and engagedwith the nozzle opening for closing the nozzle opening; delay ignitionmeans connected to the nozzle plug and pusher plate for igniting uponexposure to expanding gases and burning for a selected period of timeafter which said delay ignition means ignite said propellant in saidmotor casing; a penetrator rod having a smaller outer diameter than amaximum outer diameter of said motor casing and connected to saidforward end of said motor casing; and a sabot engaged around saidpenetrator rod and having an outer diameter substantially equal to anouter diameter of said pusher plate; whereby the kinetic energypenetrator assembly can be launched from a barrel bore by expandinggases in the barrel bore aft of the pusher plate, and the propellantcharge can be ignited after the penetrator assembly leaves the gunbarrel.
 2. An assembly according to claim 1, wherein said sabot isdesigned to break away from said rod when the penetrator assembly leavesa barrel bore.
 3. An assembly according to claim 1, including arearwardly outwardly tapering nose faring connected to a forward end ofsaid rod.
 4. An assembly according to claim 3, wherein said motor casinghas a forward outer diameter substantially equal to an outer diameter ofsaid rod and a rearward cylindrical portion having the maximum casingdiameter and substantially equal in diameter to said pusher plate.
 5. Anassembly according to claim 1, including a slip spin-ring engaged on anouter surface of said pusher plate for transmitting some spin of riflingin a barrel bore for launching the penetrator assembly, to thepenetrator assembly.
 6. An assembly according to claim 5, including arearwardly outwardly tapering nose faring connected to a forward end ofsaid rod, said casing having a tapered forward end tapering outwardlyand rearwardly from a diameter of said rod to said maximum diameterthereof, said casing including an aft cylindrical portion having saidmaximum diameter and said pusher plate having said maximum diameter. 7.An assembly according to claim 6, wherein said delay ignition meanscomprises an initiator extending through a central bore of said pusherplate and a central bore of said nozzle plug, said initiator having acentral bore and a delay charge in said central bore of said initiatorwhich is ignitable upon exposure to expanding gases and burns for aknown period of time.
 8. An assembly according to claim 7, including aconnecter connected between said rod and said forward end of saidcasing, said connecter having a central threaded bore threadablyreceiving a portion of said rod, and a nut engaged with an interior ofsaid casing and threaded into said threaded bore of said connecter. 9.An assembly according to claim 8, wherein said forward end of saidcasing is rounded, said connecter having a rear concavely roundedsurface for receiving said forward rounded end of said casing.
 10. Anassembly according to claim 9, including a plurality of radiallyextending rib supports in said casing space for supporting saidpropellant.
 11. An assembly according to claim 10, wherein said pusherplate has a concavely dished aft surface for receiving expanding gases.12. An assembly according to claim 11, wherein said casing includes aninsulating liner between said casing and said propellant.